Mercedes-Benz A-Class/A160 - rust inside car. - lemon cake

I have a April 2012 A160 purchased in April 2013. For 6 months or so I did not notice there was rust under the drivers seat ie on the seat frame work and on the supporting rails attached to to the floor. the passenger seat is not effected. Mercedes is refusing to rectify the rust ie claiming not a manufactoring fault. It may be that I will have to remove the seat and fix it. Question, where did this rust come from, has any one experienced a similar fault. I am adament that this rust must have been there on delivery. I have not carried exposed water or acid on the rear floor.

Any advice most welcome

Lemon cake.

Mercedes-Benz A-Class/A160 - rust inside car. - Bolt

If its only surface rust it may have appeared overnight,if it has paintwork it may have been scratched, cars get damp overnight and rust appears,

if its on the rail/runner try greasing it, assuming its on the inside of runner,(it should be greased anyway as its a moving part when seat adjusted)